The structure of kagome superconductors CsV$_3$Sb$_5$ in the charge density wave states

TL;DR

This study uses first-principles calculations to identify the tri-hexagonal structure as the correct charge density wave state in CsV$_3$Sb$_5$ kagome superconductor, aligning with experimental NQR and NMR data.

Contribution

It provides a systematic computational analysis that clarifies the charge density wave structure in CsV$_3$Sb$_5$, resolving previous ambiguities.

Findings

NQR spectra support the tri-hexagonal structure.

NMR calculations are consistent with experimental data.

The tri-hexagonal structure is identified as the proper CDW state.

Abstract

The structure of charge density wave states in AV$_3$Sb$_5$ (A = K, Rb, Cs) kagome superconductors remains elusive, with three possible $2a\times2a\times2c$ candidates: tri-hexagonal, star-of-David, and their mixture. In this study, we conducted a systematic first-principles investigation of the nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) spectra for the $2a\times2a\times2c$ CsV$_3$Sb$_5$ structures. By comparing our simulations with experimental data, we have concluded that the NQR spectrum indicates the tri-hexagonal structure as the proper structure for CsV$_3$Sb$_5$ after its charge density wave phase transition. The NMR calculation results obtained from the tri-hexagonal structure are also consistent with the experimental data.